Seasonal Variations in Birth Patterns in Greece: A Comprehensive Analysis of National Data From 1956 to 2022.

introductionThe seasonality of human births has been studied globally for over two centuries, revealing diverse patterns across populations shaped by intricate interactions involving both biological and socio-cultural factors. This study offers a thorough examination of national birth data in Greece spanning from 1956 to 2022, aiming to elucidate long-term trends and changes in seasonal birth patterns. MATERIALS AND

methodsData on live births in Greece were categorized by month based on national registries, and the analysis of birth seasonality was conducted annually. The Edwards method was utilized to evaluate birth seasonality by calculating the peak angle (PA), which identifies the center of the seasonal birth distribution. Additionally, the peak-to-low ratio (PLR) was computed for each year to serve as an indicator of the amplitude of birth seasonality. To investigate trends and temporal changes, joinpoint regression analysis was employed, specifically focusing on the annual percentage change (APC) within defined segments, along with a 95% confidence interval (95% CI).

resultsA total of 8,144,465 live births were recorded between 1956 and 2022. Birth seasonality was statistically significant for all examined years. The results revealed a progressive shift in the concentration of births to the second half of the year, transitioning from a peak in January and February to two significant major peaks in July and September. Additionally, in the last two decades, the lowest birth rates were observed in spring, particularly in April, as well as in December. The PA shifted significantly over time, moving from mid-January in 1956 to late August in 2022, with an APC of 39.6 (95% CI: 17.4 to 99.7) during 1956-1960 and 7.5 (95% CI: 2.2 to 11.3) during 1960-1975. Between 1975 and 2022, the trend continued at a lower stable rate (APC = 1.0, 95% CI: 0.2 to 1.5). The PLR, after a brief upward trend during 1956-1960 (APC = 6.0, 95% CI: 3.1 to 11.3), exhibited a statistically significant decline in seasonal amplitude from 1960 to 1992 (1960-1964: APC = -5.5, 95% CI: -8.6 to -2.4, 1964-1992: APC = -0.4, 95% CI: -0.8 to -0.2), and relatively stabilized during the last thirty years (1992-2022).

conclusionsThis study highlights significant changes in birth seasonality in Greece, marked by a shift in the distribution of births toward the second half of the year and a transition from peaks in births during January and February to two major surges in July and September. These trends reflect evolving reproductive behaviors in the Greek population and hold important implications for reproductive and perinatal healthcare in the country.